Lead pipe solder?

[steve in kc]

Out of the 65lbs of dead soft lead pipe I melted down into ingots a few weeks ago, there were two pieces, which I have been told are called 'boots'? They appeared to be a cylinder/cannister that had a pipe coming straight in from the top and then another coming out the side of the cannister at a 45º angle. One of these had a brass clean out on the very bottom, the other one had a sealed, smooth lead bottom.

The section where the 45º angle pipe was coming out appeared to be soldered on. The solder was still shiny with NO oxidation like the rest of the pipe which was dull, flat gray.

I'm assuming this is some type of tin or tin/lead solder? I can't imagine it being pure lead that was used to solder because of the lack of oxidation AND the fact that pouring molten pure lead over a joint 'could' cause the pipes being soldered together to become weak or melt themselves.

Ideas?

I'm thinking I have a VERY tin rich alloy in the 5% range?

Plan on making some 50/50 and 3:1 (pure to ww) alloy's. I don't want to invest in extra tin if I don't have to and am thinking I won't need to.

[imashooter2]

Probably 50/50 which was very popular for the task.

[Jim]

Without a photo, it sounds like what you have is a very old grease separator. When I started as an apprentice plumber in the late 70's, the older journeymen used 50/50 to solder pure lead joints. I can't say for sure that's what is in the joint on your piece, but I suspect so.

[KYCaster]

Sounds like Jim knows his plumbing...some kind of trap.

For a VERY ROUGH estimate of the ammount of Sn in the solder joints, measure the length of the joint, (the end cap on a 4" trap = 12.5" joint) double that, (2 ft is close enough) and you have the length of 9 ga. wire solder it took to make the joint.

The solder is roughly 1/2 oz. per foot so your joint contains one ounce of solder...1/2 oz. of Sn.

So a 4" dia. trap with 2" pipes in and out would have used about 6 ft. of solder...1 1/2 oz. of Sn. Just guessing the total weight at ~10 lbs. That would be a little less than 1% Sn.

Also, the lead very likely contains a small amount of Antimony...1/2 to 3%.

I would cast some boolits with it....air cool some and water quench some. Give them a week or so to age, then compare the hardness. If the quenched boolits show a significant increase in hardness then there is some Sb present.

Good luck
Jerry